1. Field of the Invention
The present invention relates to an improved process for the preparation of vinylaminosilanes and, in particular, to a hydrosilation process for producing a high yield of vinylaminosilanes of high purity.
2. Description of the Prior Art
The hydrosilation reaction was discovered about 1947 and, over the years, has become one of the best known and most widely practiced reactions in organosilicon chemistry. It enjoys a broad spectrum of large scale commercial applications and has been the subject of thousands of publications and extensive reviews, including the following monographs:
E. Lukevics and M. G. Voronkov, Organic Insertion Reactions of Group II Elements, Consultants Bureau, N.Y., 1966;
C. Eaborn and R. W. Boh, Organometallic Compounds of the Group IV Elements, Dekker, N.Y., 1968, Vol. I;
M. G. Pomerantseva et al, Preparation of Carbafunctional Organosilanes by an Addition Reaction, Moscow, 1971;
E. Lukevics, Russ. Chem Rev., 46, 264 (1977) and
E. Lukevics et al, J. Organometal Chem. Library 5, 1977, pp. 1-179
Various classes of platinum compounds have been found to be effective hydrosilation catalysts. Chloroplatinic acid, which is a soluble form of platinum, has proved to be an especially effective hydrosilation catalyst, as disclosed in U.S. Pat. No. 2,823,218 issued Feb. 11, 1958. It has also been reported that disilazanes, such as 1,3-dihydrodisilazane and cyclosilazanes, such as tetramethylcyclotetrasilazane, undergo slow catalytic hydrosilation with vinyl unsaturated compounds in the following articles:
K. A. Andrianov et al, Izv. Akad. Nauk SSSR, Ser, Khim. 1968, pp. 351-6;
K. A. Andrianov et al, Ibid, 1969, pp. 1539-45;
E. P. Lebedev and V. O. Reikhsfel'd, Zhur, Obshch. Khim, 38, 655, (1968) and
E. P. Lebedev and V. O. Reikhsfel'd, Ibid, 40, 1082, (1970)
It has also been reported that mono- bis- and tris(dialkylamino)silanes show little or no reactivity for hydrosilation. That lack of reactivity has been attributed to the inability of such alkylaminosilanes to form intermediate catalytic complexes with a platinum hydrosilation catalyst, W. B. Dennis and J. L. Speier, J. Org Chem. 35, 3879 (1970).
It has been more recently disclosed that a hydrosilation mechanism is possible for the reaction of hydroaminosilanes with arylacetylenes, I. M. Gverdtsiteli et al, Soobshch Akad. Nauk Gruz. SSR, 84, 381 (1976) and I. M. Gverdtsiteli et al, Tezisy Dokl-Vses. Konf. Khim. Atsetilena, 5th, 1975, 172. It was reported therein that dimethyl diethylamino silane, diethyl morpholino silane and methyl diethylamino morpholino silane reacted with diphenylacetylenes (RC.tbd.RC) via a hydrosilation mechanism to provide diphenylvinyl-substituted aminosilanes in yields only to 40 to 50 percent of the theoretical. It was also reported that attempted hydrosilations with monophenyl acetylene (RC.tbd.CH) resulted in a dehydrocondensation reaction which yielded an acetylenic, rather than a vinyl, adduct. Such arylacetylene reactions were typically run at reaction temperatures between about 20.degree. to 100.degree. C.
Vinylaminosilanes are well known to the art as illustrated in U.S. Pat. No. 3,485,857 issued Dec. 23, 1969 and U.S. Pat. No. 3,445,425, issued May 20, 1969. Such compounds are considered to be useful intermediates and highly reactive coupling agents.